Sean Linden (U. Virginia)

July

A Census of Star Clusters And Star Forming Regions in Extreme Extragalactic Environments

In order to build a complete theory of the role of star and cluster formation in galaxy evolution we need accurate measurements of the current (i.e., ~few Myr) SFR and available gas content within galaxies over a broad range of physical scales (~10 - 1000 pc) and ISM properties. Local luminous infrared galaxies (LIRGs) are the ideal laboratories for studying star formation in the most extreme merger-driven environments; conditions which may be analogous to the star-forming environment of high-redshift galaxies. With both Hubble Space Telescope (HST) and Jansky Very Large Array (VLA) data as part of the Great Observatories All-Sky LIRG Survey (GOALS) we are able to make fundamental conclusions about the nature and (in the case of star clusters) fate of both obscured and unobscured star formation in these systems. Here, I will discuss my work in identifying and characterizing the UV-bright population of super star clusters (SSCs) in two samples of GOALS LIRGs with HST. A major result of this work is the discovery that, relative to the normal star-forming galaxies studied in surveys such as the Legacy Extragalactic UV Survey (LEGUS), the survival rate and maximum mass of SSCs is affected by the active merging-environments of LIRGs. Additionally, by imaging the resolved (<1”) 1 – 33 GHz continuum emission in 25 LIRGs we have shown that 33 GHz emission from extranuclear star-forming regions in both normal and extreme star-forming galaxies is heavily-dominated by thermal free-free radiation (~90%) on ~100 pc scales, making it one of the most direct and universal probes of the ionizing photon production rate from massive star-forming regions, free from the complications of spatially varying dust extinction.

Date: 12:15 PM, July 29th, 2020

Location: Online Only

Category: Science Talk